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51.
Despite the existing regulations and standards at national and international level, web content is still difficult to use, if not completely unusable, for visually impaired people. This paper presents the evaluation results for three municipal web sites. A combined method, based on conformance review and expert review, was employed. Overall, the results reveal a low conformance to WCAG2 and many accessibility and usability problems. The content is not properly structured, and this reduces usability even for sighted user. The analysis of the evaluation data suggests that many accessibility barriers could be avoided by adopting a user-centered approach during web design.  相似文献   
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In this study, new refractory coatings based on synthesized cordierite for the casting applications were developed. The investigation included starting raw materials characterization, synthesis of the cordierite, design of the refractory coating as final product, and its application testing. The obtained results pointed out that coating suspension sediment stability was crucial quality parameter. Design and optimization of the coatings composition, with controlled rheological properties included, were achieved by application of different coating components, namely different suspension agents and by alteration of the coating production procedure. Cordierite, used as filler, was obtained by means of synthesis in the solid‐state reaction on the basis of talc, kaolin, and alumina. The investigation showed that the application of these particular types of water/alcohol‐based coatings has positive influence on surface quality and structural and mechanical properties of the castings of aluminum alloys obtained by casting into sand molds by means of evaporable models method, that is, evaporate pattern casting process.  相似文献   
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The present work describes the preparation of a set of new polyurea polymers suitable for ballistic protection applications by employing different aromatic diamines derivatives with different flexibility degrees. This modification would allow the synthesis of polymers with both enhanced and controllable mechanical properties through the combination of aliphatic and aromatic molecules. Besides the classical methylene diphenyl diisocyanate and polypropylene glycol bis(2‐aminopropyl ether) (PPG), benzidine, 4,4′‐diaminodiphenylmethane and 3,6‐diamino carbazole were chosen as the third monomer and used in different ratios toward PPG, in order to optimize the polymer properties. The proportions between the polyurea components were selected as such to achieve the total consumption of the monomers. The different types of polyurea obtained have been characterized by Fourier transform infrared spectroscopy, thermal measurements (differential scanning calorimetry and thermogravimetric analysis), tensile tests, and scanning electron microscope. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43967.  相似文献   
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The present study investigated the capacity of formulated Berberis vulgaris extract/β-cyclodextrin to protect liver against CCl(4)-induced hepatotoxicity in mice. Formulated and non-formulated extracts were given orally (50 mg/kg/day) to mice for 7 days and were then intra-peritoneally injected with 1.0 mL/kg CCl(4) on the 8th day. After 24 h of CCl(4) administration, an increase in the levels of apartate-amino-transferase (AST), alanine-amino-transferase (ALT) and malondialdehyde (MDA) was found and a significant decrease in superoxide-dismutase (SOD), catalase (CAT), glutathione (GSH) and glutathione-peroxidase (GPx) levels could be detected. This was accompanied by extended centrilobular necrosis, steatosis, fibrosis and an altered ultrastructure of hepatocytes. Pre-treatment with formulated or non-formulated extract suppressed the increase in ALT, AST and MDA levels and restored the level of antioxidant enzymes at normal values. Histopathological and electron-microscopic examination showed milder liver damage in both pre-treated groups and the protective effect was more pronounced after the formulated extract was administered. Internucleosomal DNA fragmentation induced by CCl(4) was reduced in the group which received non-formulated extract and absent in the group which received formulated extract. Taken together, our results suggest that Berberis vulgaris/β-cyclodextrin treatment prevents hepatic injury induced by CCl(4) and can be considered for further nutraceutical studies.  相似文献   
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We analyze in detail the morphology transition of poly(ethylene oxide)-b-poly(N-isopropylacrylamide) (PEO-b-PNIPAM) diblock copolymer in water with small angle neutron scattering. A three-level hierarchical structure is found below the critical solution temperature (LCST) of PNIPAM. The small-scale structure corresponds to the unperturbed PEO-b-PNIPAM chains. These coils assemble into intermediate-size aggregates which have a constant number density in solution, independently of the solution concentration, under the assumptions of a simple model based on the concentration dependence of the fitting parameters. Large clusters are also observed, which comprise the large-size structure. Above the LCST the system transforms into a well-defined geometry of monodisperse elliptical vesicles which does not depend on the solution concentration. The vesicles become less asymmetric with a higher aggregation number at the highest temperature.  相似文献   
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Practical protocols for certified electronic mail   总被引:32,自引:0,他引:32  
Electronic mail, or e-mail, has brought us a big step closer towards the vision of paperless offices. To advance even closer to this vision, however, it is essential that existing e-mail systems be enhanced with value-added services which are capable of replacing many of the human procedures established in pen and paper communications. One of the most important and desirable such services is certified e-mail delivery, in which the intended recipient will get the mail content if and only if the mail originator receives an irrefutable proof-of-delivery from the recipient. In this paper, we present the design of two third-party based certified mail protocols, termed CMP1 and CMP2. Both protocols are designed for integration into existing standard e-mail systems and both satisfy the requirements ofnonrepudiation of origin, nonrepudiation of delivery, and fairness. The difference between CMP1 and CMP2 is that the former provides no mail content confidentiality protection while the latter provides such a protection. Moreover, security of the protocols are analyzed using a recently proposed accountability framework.  相似文献   
60.
The scaling behavior of the effective activation energy U(T, H) of epitaxial oriented Bi2Sr2Ca1–x Er x Cu2O8+d thin films with 0x0.10 has been studied as function of temperature and magnetic field. It has been found that the activation energy scales as U(H, T)=U 0(1–t)m H n with exponent m=1.20±0.03 and n=–1/2. The field and temperature dependence of the activation energy, as well as its overall magnitude, is consistent with a model in which U(T, H) arises from plastic deformations of viscous flux liquid above the vortex-glass transition temperature.  相似文献   
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